Automatic leveling ladder



' Feb. 23, 1937.

c E. BOWERS AUTOMATIC LEVELING LADDER Filed Dec. 28, 1954 2 Sheets-Sheet1 FIG. 1

INVENTOR C/m/de f. 5014/2/25 A TTORNEY Feb. 23, 1937. c. E. BOWERSAUTOMATIC LEVELING LADDER 2 Sheets-sheaf 2 Filed Dec. 28, 1954 v saa gFIG. 6

FIG. 7

IA I-IENTO/x f. Bowers A TTORNE 1 Patented Feb. 23, 1937 UNITED STATESPATENT OFFICE AUTOMATIC LEVELING LADDER Claude E. Bowers, Los Angeles,Calif. Application December 28, 1934, Serial No. 759,496 9 Claims. (01.228-29) My invention relates to ladders, more particularly to a ladderin which the legs will automatically shift to conform to uneven surfacesupon which the ladder may be positioned while the main portion of theladder remains substantially level, and the objects of my invention are:

First, to provide a ladder which is strong and durable and in which thelegs of the ladder will automatically shift to accommodate the ladder touneven surfaces on which it may be positioned;

Second, to provide a ladder of this class in which the weight of aperson stepping on the ladder will automatically shift the legs of theladder;

Third, to provide a ladder of this class with stop means to prevent therelative shifting of the legs too far so that the ladder will tip;

Fourth, to provide a step ladder of this class with means for rigidlysecuring the legs in various adjustable positions;

Fifth, to provide a means for providing frictional relation between theshiftable legs and their supports so that the legs tend to shift onlywhen sufficient weight is brought to bear on the steps of the ladder;

Sixth, to provide a ladder of this class in which the parts .are sorelated in their cooperative relation that great strength and durabilityis provided, and

Seventh, to provide a step ladder of this class which is very simple andeconomical of construction, automatic in its action, durable andefficient.

With these and other objects in view as will appear hereinafter, myinvention consists of certain novel features of construction,combination and arrangement of parts and portions as will be hereinafterdescribed in detail and particularly set forth in the appended claims,reference being had to the accompanying drawings and to the charactersof reference thereon which form'a part of this application, in which:

Figure l is a rear elevational view of the ladder in step-ladder formshown with the legs substantially positioned on a level surface; Fig, 2is a similar view showing one of the rear legs elevated and the adjustedrelation of the other parts of the platform and steps are substantiallylevel; Fig. 3 is a side elevational view of the ladder on a reducedscale; Fig. 4 is an enlarged fragmentary sectional view through 4- 3 ofFig. 1; Fig. 5 is a further enlarged sectional view showing the clampand its relation on an enlarged scale; Fig. 6 is a fragmentary enlargedview of the equalizing bar and its relation with the equalizing strut,and Fig. '7 is a sectional View thereof through 1-1 of Fig.6.

Similar characters of reference refer to simi- 5 lar parts and portionsthroughout the several views of the drawings.

The front legs I, back legs 2 and 3, equalizing bar 4, equalizing strut5, back leg supporting members 6 and I, combined reinforcing and supportmembers 8, platform 9, clamps l0, and brace members H and I2, constitutethe principal parts and portions of my ladder as disclosed instep-ladder form.

The front legs I are of conventional form and positioned in spacedrelation. Mounted between these front legs l are step members Iasupported by tie rods lb, all in the conventional manner. Secured to theupper ends of the legs I in rigid relation is a platform 9, also of theconventional type and secured in conventional manner by means ofbrackets 9a, one on each side. Pivotally supported on these brackets 9ware the back leg supporting members 6 and 'l which are hollow,preferably oblong in cross-section, as shown, and they are reinforced attheir upper ends by combined reinforcing and stop members 8, shown bestin Fig. 4 of the drawings, which which form a reinforcing for the upperends of the hollow supports 6 and 'I and also form a stop to preventextreme shifting of the leg members 2 and 3 upwardly in their respectivesupports 6 and I. The leg members 2 and 3 are telescopically mounted inthe members 6 and I and their outer surface adapted to conform to 35 theinner surface of the members 6 and 'l for the telescopic shifting of themembers 2 and 3 in the members 6 and I. Mounted around the lower ends ofthe members 6 and l are clamp bands In which are provided in one side,preferably the back side as shown, with wing screws Illa which engage aspring member lob, shown best in Fig. 5 of the drawings, thus providingmeans for slightly distorting portions of the lower end of the members 6and 1 and pressing them against the upper ends of the members 2 and 3 toprovide friction between the members 2 and 3 and the members 6 and I,and when sufficient pressure is brought thereon to lock the members 2and 3 relative to the members 6 and I.

Pivotally connected toward the lower end of the members 2 and 3 is anequalizing bar 4. This equalizing bar is preferably positioned on thefront side of the leg members 2 and 3, as shown,

and it is provided on its back side with a member 4a which is providedwith a circular recess 4?) in its upper side which is adapted to receivethe lower rounded end Ea of the strut member 5 so that this end 5a restson the upper surface of the groove 4b substantially in alinement withthe leg members 2 and 3. The upper end of this strut member 5 is hingedto the platform 9 by means of a hinge 52) so that the strut member 5 issubstantially in alinement with the supports 5 and i.

The brace members H and 52 are of the conventional interlocking type.The one ends of the members l2 are secured to the leg members I and themembers I l are secured to the strut 5. It will be noted that themembers i! and 12 are of the convention-a1 type of step-ladder brace andtend to spread the leg members i from the members 2 and 3 and hold themin spread relation by means of the strut member 5.

The operation of the ladder is as follows: The ladder is positioned onthe ground with the back legs positioned on uneven surface. Then with aperson stepping on the steps I a the legs 2 and 3 will be raised andlowered relatively to each other conforming to the surface upon whichthey are positioned and the equalizing member 4 will shift, as shown inFig. 2 of the drawings, while the platform 9 and steps I a remain insubstantially horizontal or level position, the leg members 2 and 3telescoping in the members 6 and However, if an extreme shift is madethe upper ends of the members 2 and 3 will engage the stop members 8 andprevent further shifting. These members may be locked by the clamp screwIlia or the friction between the members 2 and 6 and the members 3 and 1increased or decreased by this clamp screw 5a.

Though I have shown and described a particular construction, combinationand arrangement of parts and portions, I do not wish to be limited tothis particular construction, combination and arrangement, but desire toinclude in the scope of my invention the construction, combination andarrangement substantially as set forth in the appended claims.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

1. In a ladder, a platform, a pair of leg members pivotally mounted onsaid platform, each of said leg members composed of two telescopicallymounted portions with the one portion of each shiftable within the otherportion, a single strut member pivotally connected with said platformintermediate said legs arranged to swing parallel with said legs, a barpivotally connected at each of its ends with said legs and supportingthe free end of said strut member in pivotal relation therewith.

2. In a ladder, a platform, a pair of leg members pivotally mounted onsaid platform, each of said leg members composed of two telescopicallymounted portions with the one portion of each shiftable within the otherportion, adjustable means for providing frictional relation between saidmembers, a single strut member pivotally connected with said platformintermediate said legs arranged to swing parallel with said legs, a barpivotally connected at each of its ends with said legs and supportingthe free end of said strut member in pivotal relation therewith.

3. In a ladder of the class described, leg members each consisting of abox like pivotally mounted telescopic member, another member telescopically mounted therein, a bar pivotally connected at its opposite ends totwo of said telescopically mounted members near their lower ends, and asingle strut member pivotally connected with said bar intermediate itsends and extending upwardly intermediate said leg members.

4. In a ladder of the class described, leg members each consisting of abox like pivotally mounted telescopic member, another membertelescopically mounted therein, a bar pivotally connected at itsopposite ends to two of said telescopically mounted members near theirlower ends, a single strut member pivotally connected with said barintermediate its ends and extending upwardly intermediate said legmembers, and a step member pivotally connected with the upper ends ofeach of said leg members and said strut member.

5. In a ladder of the class described, a pair of front legs, a platformrigidly connected to the upper ends of said front legs, back legspivotally connected with said platform, each of said back legsconsisting of two telescopically mounted members, a single strut memberpivotally mounted on said platform intermediate said back leg members, abar pivotally connected at its ends to the lower members of said backleg members and pivotally engageable with said strut member at its lowerend.

6. In a ladder of the class described, a pair of front legs, a platformrigidly connected to the upper ends of said front legs, back legspivotally connected with said platform, each of said back legsconsisting of two telescopically mounted members, a single strut memberpivotally mounted on said platform intermediate said back leg members, abar pivotally connected at its ends to the lower members of said backleg members and pivotally engageable with said strut member at its lowerend, and adjustable brace means connecting said strut member with thefront leg members intermediate the ends of said leg members and saidstrut member.

7. In a ladder of the class described, a pair of front legs, a platformrigidly connected to the upper ends of said front legs, back legspivotally connected with said platform, each of said back legsconsisting of two telescopically mounted members, a single strut memberpivotally mounted on said platform intermediate said back leg members, abar pivotally connected at its ends to the lower members of said backleg members and pivotally engageable with said strut member at its lowerend, adjustable brace means connecting said strut member with the frontleg members intermediate the ends of said leg members and said strutmember, stop means in connection with said telescopic members forlimiting the relative movement of said telescopic members and each legmember.

8. In a ladder of the class described, a pair of front legs, a platformrigidly connected to the upper ends of said front legs, back legspivotally connected with said platform, each of said back legsconsisting of two telescopically mounted members, a single strut memberpivotally mounted on said platform intermediate said back leg members, abar pivotally connected at its ends to the lower members of said backleg members and pivotally engageable with said strut member at its lowerend and also provided with a recess to receive said lower end,adjustable brace means connecting said strut member with the front legmembers intermediate the ends of said leg members and said strut member,and means for providing friction between the telescopic members of eachleg member.

9. In a ladder of the class described, a pair of front legs, a platformrigidly connected to the upper ends of said front legs, back legspivotally connected with said platform, each of said back legsconsisting of two telescopically mounted members, a single strut memberpivotally mounted on said platform intermediate said back leg members, abar pivotally connected at its ends to the lower members of said backleg members and pivotally engageable with said strut member at its lowerend and also provided with a recess to receive said lower end,adjustable brace means connecting said strut member with the front legmembers intermediate the ends of said leg members and said strut member,stop means in connection with said telescopic members for limiting therelative movement of said telescopic members and each leg member, andmeans for providing friction between the telescopic members of each legmember.

CLAUDE E. BOWERS.

